During the production and purification process of a hydroxycarboxylic acid, for example lactic acid, the hydroxycarboxylic acid is evaporated or distilled from less-volatile compounds present in a partially purified fermentation broth. These less-volatile components, which contain significant amounts of hydroxycarboxylic acid in the form of oligomers of hydroxycarboxylic acid and saccharide esters, are purged out of the system as waste, which incurs a significant yield loss, as well as solid waste disposal costs. Thus, it is desirable to turn such waste streams into something having economic benefit.